© The Author 2006. Published by Oxford University Press.
CORRESPONDENCE |
Re: Survival Effects of Postmastectomy Adjuvant Radiation Therapy Using Biologically Equivalent Doses: A Clinical Perspective
Correspondence to: Carl D. Atkins, MD, South Shore Hematology-Oncology Associates, 242 Merrick Rd., Ste. 301, Rockville Centre, NY 11570 (e-mail: catkins{at}alum.mit.edu).
I agree with Gebski et al. (1) that consideration of radiation therapy technique is important when interpreting meta-analyses of postmastectomy therapy for breast cancer. The same should hold true, however, for surgical technique. The pooled analyses of overall mortality in both the authors' study and the Early Breast Cancer Trialists' Group overview are heavily influenced by the three large Scandinavian trials, which showed some of the largest survival benefits (2). In the Danish trials, axillary lymph node dissection "included removal of the central axillary lymph nodes involving level I and part of level II," and the median number of lymph nodes removed was only seven (3,4). In contrast, a series of patients reported from Kaiser Permanente Medical Center had a median of 18 lymph nodes removed, with only 3% of specimens containing fewer than 12 lymph nodes (5). In the Stockholm trial, surgery "generally included dissection of lymph nodes at level I and II below the axillary vein," but the number of resected lymph nodes "was not routinely reported" (6). These data raise concern that the benefit of postmastectomy radiation therapy may be limited to patients who do not have adequate surgical axillary lymph node clearance. This issue is important because the incidence of arm edema after radiation therapy increases with the extent of axillary surgery (7). If modified radical mastectomy with full dissection of level I and II lymph nodes confers the same benefit as radiation therapy after less axillary surgery, the addition of adjuvant radiation therapy could increase morbidity without improving survival. Because the Scandinavian studies were included in their "optimal dose" category, the finding of Gebski et al. that statistically improved survival in this group could result from the need for better local treatment after suboptimal surgery may not be generalizable to patients with adequate axillary lymph node clearance.
REFERENCES
(1) Gebski V, Lagleva M, Keech A, Simes J, Langlands AO. Survival effects of postmastectomy adjuvant radiation therapy using biologically equivalent doses: a clinical perspective. J Natl Cancer Inst 2006;98:26–38.
(2) Early Breast Cancer Trialists' Collaborative Group. Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials. Lancet 2005;366:2087–106 (see Web Fig. 8b).[Web of Science][Medline]
(3) Overgaard M, Hansen PS, Overgaard J, Hansen PS, Rose C, Bach F, et al. Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy: Danish Breast Cancer Cooperative Group 82b Trial. N Engl J Med 1997;337:949–55.
(4) Overgaard M, Jensen M-B, Overgaard J, Hansen PS, Rose C, Andersson M, et al. Postoperative radiotherapy in high-risk postmenopausal breast cancer patients given adjuvant tamoxifen: Danish Brest Cancer Cooperative Group DBCG 82c randomised trial. Lancet 1999;353:1641–8.[CrossRef][Web of Science][Medline]
(5) Patterson S, Ko A, O'Connell TX. Radiation after mastectomy in high-risk patients: is it necessary? Ann Surg 2001;67:1209–12.
(6) Rutqvist LE, Pettersson D, Johansson H. Adjuvant radiation therapy versus surgery alone in operable breast cancer: long-term follow-up of a randomized clinical trial. Radiother Oncol 1993;26:104–10.[CrossRef][Web of Science][Medline]
(7) Larson D, Weinstein M, Goldberg I, Silver B, Recht A, Cady B, et al. Edema of the arm as a function of the extent of axillary surgery in patients with stage I–II carcinoma of the breast treated with primary radiotherapy. Int J Radiat Oncol Biol Phys 1986;12:1575–82.[Web of Science][Medline]
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J Natl Cancer Inst 2006 98: 1021-1022.
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